Positioning element

ABSTRACT

An alignment element for securing a fuel injector, for the direct injection of fuel into the combustion chamber of an internal combustion engine, to a cylinder head of the internal combustion engine in a manner to ensure locking against rotation includes a ring that is slipped onto the fuel injector, provided on the ring is at least one plug that is arranged on the ring, slipped onto the fuel injector, in such a manner that it is able to snap into a recess in a plastic coating of the fuel injector.

FIELD OF THE INVENTION

The present invention relates to an alignment element for locking a fuelinjector, mounted in a cylinder head of an internal combustion engine,against rotation.

BACKGROUND INFORMATION

Fuel injectors for the direct injection of fuel into the combustionchamber of a mixture-compressing internal combustion engine havingexternally supplied ignition may be held down in the cylinder head by aclamping shoe that is bolted to the cylinder head of the internalcombustion engine. Such a clamping shoe is discussed, for example, inJapanese Patent Application No. 831 25 03. In that case, the clampingshoe presses on a shoulder of the fuel injector and thereby is securesit in the receiving bore hole of the cylinder head. The clamping shoe istightened so securely by a suitable tool, e.g., a torque wrench, thatthe fuel injector may not be I forced out of the cylinder head by thepressure prevailing in the combustion chamber of the internal combustionengine.

The fixing device discussed in Japanese Patent Application No. 831 25 03may not provide protection for the fuel injector, held down by thefixing device, against rotation in the cylinder head. Due to thevibrations occurring during operation of the internal combustion engine,the fuel injector may twist in its fitting position relative to thecylinder head, which means, for example, the electric cable connectionsfor actuating the fuel injector and the fuel distributor lineflange-mounted on the fuel injector may be damaged. The subsequentmalfunctions may lead to damage to the fuel injector, as well as theentire internal combustion engine.

SUMMARY OF THE INVENTION

In accordance with an example embodiment of the present invention, analignment element, connectable to a fuel injector by catching via aplug, for a fuel injector is provided which may fix the fuel injector inposition in such a manner that rotation of the fuel injector in itsfitting position is prevented, and therefore no damage may occur as aresult of sheared-off cable or distributor lines.

The alignment element may be provided with a tab which is clamped as alever arm for reliable securing between the fuel injector and, forexample, a mandrel of a fixing device. The mandrel may also penetratethe tab through an opening.

The alignment element may be produced in one piece from sheet metal bypunching and bending, which means it exhibits good elasticity propertiesthat are necessary for engaging with the fuel injector.

The alignment element may be mounted without additional componentsbetween the fuel injector and the mandrel of the fixing device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic partial section through a fuel injector fixedin position in a cylinder head of an internal combustion engine by anexample embodiment of an alignment element according to the presentinvention.

FIG. 2 shows a schematic top view of the example embodiment of analignment element according to the present invention shown in FIG. 1,with a first securing possibility.

FIG. 3 shows a cut-away portion from FIG. 2 of the example embodiment ofan alignment element, according to the present invention, with a secondsecuring possibility.

DETAILED DESCRIPTION

FIG. 1 shows a schematic partial section through a fuel injector 1,which is locked against rotation in a cylinder head 2 of an internalcombustion engine by an alignment element 8 according to an exampleembodiment of the present invention.

In this context, a fuel injector 1 is configured in the form of adirect-injection fuel injector 1, which is installed in a cylinder head2 for the direct injection of fuel into a combustion chamber of amixture-compressing internal combustion engine (not shown further)having externally supplied ignition. At an end 3 on the inlet side, fuelinjector 1 is provided with a plug connection to a fuel distributor line(not shown), which is sealed by a seal 4 between the fuel distributorline and a supply line connection 5 of fuel injector 1. Fuel injector 1includes an electrical connection 6 for the electrical contacting toactuate fuel injector 1. Fuel injector 1, at least in its partprojecting above cylinder head 2, is provided with a plastic coating 9that also surrounds electrical connection 6.

In order to lock fuel injector 1, fixed in position in a receiving borehole 7 of cylinder head 2 by a fixing device, e.g., a clamping shoe (notfurther shown), against rotation, an alignment element 8 is provided.Alignment element 8 is made of a ring 10 which, in the exampleembodiment, includes at least one plug 11 used for fixing ring 10 toplastic coating 9. The at least one plug 11 engages in a correspondingrecess 12 of plastic coating 9, whereby ring 10, slipped onto fuelinjector 1, is detachably joined to it.

A tab 13, formed on ring 10, extends parallel to the surface of cylinderhead 2 to a structure, suitable as an abutment (counter-support), whichis securely joined to cylinder head 2. In the example embodiment, it isa mandrel 15 of the fixing device (not further shown), which, forexample, may be configured in the form of a clamping shoe. In thiscontext, tab 13 acts as a lever arm which permits reliable locking offuel injector 1 against rotation in its fitting position in cylinderhead 2.

Additionally, the at least one plug 11 may be arranged asymmetrically inrelation to the position of tab 13 on the periphery of ring 10, so thatthe mounting position of alignment element 8 is clearly defined. Thismeasure is apparent from the top view of alignment element 8 in FIG. 2,in which ring 10 is shown with tab 13 extending radially outwardly. Itmay thereby be ensured that alignment element 8 is slipped onto fuelinjector 1 in the correct orientation during assembly.

In addition, to avoid slipping off from mandrel 15 used as an abutment,tab 13 is configured asymmetrically at an end 14 facing away from ring10, so that it may not drift between mandrel 15 and fuel injector 1.This may be achieved, for example, by a contour of end 14 of tab 13partially encompassing mandrel 15. Thus, after plug 11 has snapped intorecess 12 on fuel injector 1, and end 14 of tab 13 has locked into placeon mandrel 15, with insignificant tolerances, fuel injector 1 isprevented from rotating, which means cable and line connections attachedto fuel injector 1 are no longer exposed to the danger of shearing off.

Alignment element 8 may be fastened directly on cylinder head 2, forexample, also using mandrel 15 by screwing it through a correspondingopening 16 in the tab into cylinder head 2, as shown in part in FIG. 3.To mount alignment element 8, it is first of all slipped onto fuelinjector 1, which is then mounted in cylinder head 2, and mandrel 15 ofthe clamping shoe is subsequently screwed into cylinder head 2 throughopening 16, so that fuel injector 1 is secured and locked againstrotation simultaneously.

The present invention is not limited to the example embodiment shown,and is also applicable, for example, to fuel injectors 1 for injectioninto the combustion chamber of a self-ignition internal combustionengine.

1. An alignment element for securing a fuel injector for directinjection of a fuel into a combustion chamber of an internal combustionengine to a cylinder head of the internal combustion engine, thealignment element comprising: a ring slipped onto the fuel injector; andat least one plug arranged on the ring which is arranged so that the atleast one plug snaps into a recess in a plastic coating of the fuelinjector.
 2. The alignment element of claim 1, wherein the recess isformed in a region of an electrical connection of the fuel injector. 3.The alignment element of claim 1, wherein a tab formed as a flatstructural element is arranged on the ring.
 4. The alignment element ofclaim 3, wherein the tab, with an end facing away from the ring, abutsagainst a mandrel of a fixing device, the mandrel functioning as anabutment.
 5. The alignment element of claim 4, wherein the end facingaway from the ring at least partially encompasses the mandrel.
 6. Thealignment element of claim 3, wherein the at least one plug and the tabare arranged asymmetrically with reference to a periphery of the ring.7. The alignment element of claim 4, wherein the tab is penetrated bythe mandrel through an opening.
 8. The alignment element of claim 3,wherein the ring is formed in one piece with the tab.
 9. The alignmentelement of claim 1, wherein the alignment element is produced from asheet metal by punching and bending.
 10. The alignment element of claim3, wherein the tab is joined to the ring by one of welding or soldering.